Quick-release connector system for footwear

ABSTRACT

A removably attachable traction gear for the underside of footwear having two primary components: a retaining member and a receptacle. These two components respectively replace the common screw and threaded receptacle systems found in for affixing traction gear to the underside of shoes. A partial turn of the traction gear securely locks the gear into the receptacle. The retaining member has a three-extension design so as to make the traction gear resistant to lateral forces applied to the ground-engaging end of the cleat. Locking is achieved through use of cantilevered fingers which press in during installation of the retaining member, and which spring back out to lock with mated indentations in the extensions. During installation a dome containing insole material is compressed. Unlocking is achieved through reverse turning the retaining member to force the springs back in, and removal is aided through re-expansion of the dome. In a preferred form, the invention is utilized to attach athletic cleats to a sport shoe.

The present application is a continuation of application Ser. No. 09/208,180, filed Dec. 9, 1998 now U.S. Pat. No. 6,108,944, which in turn is a continuation-in-part of application Ser. No. 09/062,037, filed Apr. 17, 1998, which in turn is a continuation-in-part of application Ser. No. 08/774,585, filed Dec. 23, 1996, which issued on Jun. 23, 1998 as U.S. Pat. No. 5,768,809, which in turn claims priority from provisional application Ser. No. 60/010,099, filed Jan. 17, 1996, and titled “Quick-Release Spike for Footwear.” These applications are incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to removably attachable mechanical connectors and the mounting of traction gear on the bottom of footwear, in particular, athletic footwear, using such connectors.

BACKGROUND ART

Conventional traction gear presently in use employ an attachment means consisting of screwing the traction gear into the mated receiving receptacle in the bottom of the footwear. Using this screw-type attachment method is especially laborious when one takes into account that a typical golf shoe, for instance, has eleven cleats; as a result, replacing the cleats on a pair of golf shoes entails unscrewing twenty-two cleats and screwing on twenty-two cleats, where each act of unscrewing or screwing entails several turns, typically two and one-half times, for each cleat.

An example of a typical prior-art cleat is in U.S. Pat. No. 4,723,366 (hereinafter the '366 cleat), which patent is incorporated herein by reference. This patent describes a cleat which includes a metal stud infrastructure at the core of the cleat, the infrastructure having a vertical axis and two ends, a screw portion at a first end for engagement with a receptacle within a shoe, a ground end for tractive engagement with the ground, and a broad flange between the screw and head portions and extending radially outward from the vertical axis; a plastic skirt is molded directly upon the flange portion to form a unitary reinforced radial support member of the cleat. Installation of the '366 cleat consists of screwing it into a mated receptacle in the bottom of athletic footwear.

Although some prior-art references show cleat-attachment systems that require less than a full turn, or they require a snap-on arrangement to lock the cleat in place, it appears none of these systems have found wide acceptance amongst users because of shortcomings in stability, ease-of-use, receptacle size and ease-of-manufacture. For instance, in U.S. Pat. No. 4,633,600 to Dassler, a cleat attachment system is disclosed in which a snap ring socket is utilized to affix a cleat to the bottom of a shoe.

In U.S. Pat. No. 3,267,593 to Turner, a cleat attachment system is disclosed wherein the top of the cleat spike has two extensions forming a rough T-shape out of the spike, where the spike is inserted into a mated receptacle having two grooves to receive the extensions. Upon complete insertion of the spike into a receptacle, the spike is turned until the extensions drop into receiving grooves at the top of the receptacle; a retaining ring is then slid onto the mid-section of the spike, this ring apparently preventing the spike from unseating the extensions from the grooves.

Similarly, in German Patent Application Nos. DE3134817A1 to Sportartikelfabrik Karl Uhl GmbH, and DE3423363A1 to Gebrüder Goldschmidt Baubeschläge GmbH, another T-spike design is disclosed in which internal to the mated receptacle are ramping means for engaging and retaining the spike extensions. In the former, a rough interior surface catches the extensions, while in the latter, a sloping interior engages the extensions.

U.S. Pat. No. 4,492,047 to Arff, discloses another T-shape spike in which the skirt is deformed during insertion. Insertion of the spike causes the extensions to go up a ramp and then down a ramp, pulling the spike into the receptacle, and leaving the extensions in a holding area. The skirt is deformed so as to result in a pressure against the socket, the pressure apparently holding the spike from accidentally traveling back up the ramp towards removal.

In U.S. Pat. No. 4,035,934 to Hrivnak, another T-shape spike is disclosed in which the spike column has two indentations. During installation, two spring arms, each positioned perpendicular to the surface of the shoe and parallel to the spike, are pressed in during insertion of the spike, and spring back out to press against the indentations upon complete insertion. Removal of this spike is achieved with a U-shaped tool which slides into the spike receptacle and pushes in the spring arms, thus freeing the spike for removal.

SUMMARY

A representative embodiment of the present invention includes a system

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings are intended to provide a better understanding of the present invention, but they are in no way intended to limit the scope of the invention.

FIG. 1 is a side view of a cleat according to one embodiment of the invention.

FIG. 2 is a top view of the cleat of FIG. 1, showing the shape of the lobes to be inserted into a mated receptacle in the bottom of athletic footwear.

FIG. 3 is another side view of the cleat of FIG. 1.

FIG. 4 is a bottom view of the cleat of FIG. 1.

FIG. 5 is a bottom view of a receptacle that may receive the FIG. 1 cleat.

FIG. 6 is a top section view of the FIG. 5 receptacle wherein the top layer of the receptacle has been removed.

FIG. 7 is a side vertical section of the receptacle of FIG. 6.

FIG. 8 is a top view of the FIG. 6 receptacle wherein the top layer has not been removed.

FIG. 9A is a perspective right side view of a cleat according to a preferred embodiment of the invention.

FIG. 9B is a perspective top view of the FIG. 9A cleat.

FIG. 9C is a perspective front view of the FIG. 9A cleat.

FIG. 9D is a perspective left view of the FIG. 9A cleat.

FIG. 10 is a top view of the cleat of FIG. 9A, showing the shape of the lobes to be inserted into a mated receptacle in the bottom of athletic footwear.

FIG. 11 is another side view of the cleat of FIG. 9A.

FIG. 12A is a top section view of a the receptacle for receiving the cleat of FIG. 9A, wherein the top layer of the receptacle has been removed.

FIG. 12B is a perspective bottom view of the FIG. 12A receptacle.

FIG. 13 is a side vertical section of the receptacle of FIG. 12A.

FIG. 14 is a bottom view of a cover for the FIG. 12A receptacle.

FIG. 15 is a side view of FIG. 14 cover.

FIG. 16 is a partial view of a FIG. 9A cleat inserted into a FIG. 12A receptacle.

FIG. 17 is a bottom view of the FIG. 9A cleat.

FIG. 18 is a top view of an unassembled receptacle for receiving the FIG. 9A cleat.

FIG. 19 is a bottom view of the FIG. 18 receptacle.

FIG. 20 is a section view of the FIG. 18 receptacle.

FIG. 21 is a side view of a cleat according to a preferred embodiment of the invention.

FIG.22 is a side view of a cleat according to a preferred embodiment of the invention showing an alternative ground-engaging “soft” golf spike.

FIG. 23 is a top view of a cleat similar to FIG. 21 showing the top of the cleat connector.

FIG. 24 is a perspective top view of the cleat of FIG. 21 in a receptacle with the top cover removed.

FIG. 25 is a top view of a cleat connector of the type shown in FIG. 23, with the addition of semi-circular dust covers.

FIG. 26 is a perspective top view of the cleat connector of FIG. 25.

FIG. 27 is a perspective bottom view of a preferred embodiment of a receptacle for receiving the cleat connector of FIG. 25.

FIG. 28 is an inverted side view of a cleat using the cleat connector of FIG. 25.

FIG. 29 is a perspective bottom view of an alternative receptacle having a center cone in the top cover.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention comprises a system for allowing the quick attachment and release of a wide variety of traction gear. FIG. 1 shows that in one embodiment of the invention, the attachment system would be used to attach cleats, such as those disclosed in U.S. Pat. No. 4,723,366, to the underside of athletic footwear a cleat installed in the bottom of a shoe using the present invention, when viewed from the bottom, has a similar appearance to the preferred embodiment of the invention disclosed herein. Evident in FIG. 1 are the bottom side 17 and top side 16 of the plastic skirt 15, the ground-engaging head portion 10 of the cleat, a base 13 to which the plastic skirt and ground-engaging portion are attached and a retaining member 20, which in this case is a base 13 with three rounded extensions 22, all of which are positioned around a central axis 28. In a preferred embodiment of the invention, the top 16 of the skirt 15 is slightly concave, and the bottom 17 of the skirt 15 is somewhat convex.

FIG. 2 shows the topside 16 of the cleat skirt 15 and the retaining member 20, which has a roughly triangular shape with indentations 26. The extensions 22 of the retaining member 20 are used in conjunction with components inside the receptacle, shown as item 30 in FIG. 5, for locking in place a properly inserted retaining member 20. Locking in place occurs after inserting the retaining member 20 into a mated receptacle opening 40 as shown in FIG. 5 and FIG. 6, and torquing the retaining member. The extensions 22 are attached to the base 13 (shown in FIG. 1), and together the extensions and the base form the retaining member 20. In a preferred embodiment of the invention, a completed cleat, comprising the retaining member 20 and traction gear, is made out of plastic with a metal core used to reinforce the structure. Although the invention could be made entirely out of metal, it is preferable that the cleat be made partially of plastic and partially of metal. When the retaining member is plastic, the retaining member may be integrally formed with a plastic skirt of a golf cleat with a core, preferably metal, extending through the retaining member and the traction gear to form the ground-engaging head portion 10 shown in FIG. 1.

In a preferred embodiment of the invention, upon insertion of the retaining member 20 into a receptacle, the angled surface 24 (shown in FIG. 1) of the extensions 22 allows for a tighter fit of the retaining member 20 into the receptacle 40 (shown in FIG. 5). The tight connection not only serves to give a stable connection between the shoe and traction gear, but also serves to keep moisture and debris out of the attachment system.

FIG. 3 is another view showing the structure and proportion of the retaining member 20 as attached to traction gear 21. FIGS. 2 and 3 show that in a preferred embodiment of the invention, the extensions 22 form a broad retaining member 20, and the base 13 is cylindrical and concentrically disposed around the center axis 28; the base 13 is attached to the extensions 22 and the traction gear 21.

FIG. 4, a bottom view of the FIG. 1 cleat, shows that, in a preferred embodiment of the invention, cleats do not have to be redesigned beyond modifying the retaining member 20 (shown in FIG. 1), and that conventional cleat designs are intended to be used in conjunction with the new retaining member; once a cleat is installed, the change in the retaining system is not apparent. A standard golf-cleat wrench may be used to engage the traction gear through use of the wrench holes 18.

FIG. 5 is a bottom view of a receptacle 30 that may receive the FIG. 1 cleat, showing the receptacle opening 40, with indentations 44 along its perimeter for accepting the retaining member extensions 22 (shown in FIG. 1). FIG. 5 also shows the ledges 46 that while serving to form the shape of the opening 40, also serve to hold the extensions 22 within the receptacle. Although preferred embodiments of the invention include a single receptacle opening 40, alternate embodiments of the system could have a receptacle with separate openings for receiving extensions.

FIG. 6 is a section view of FIG. 5 where the top layer of the receptacle has been removed to show the inner-cavity structure for receiving the retaining member 20 (shown in FIG. 1). Within the cavity, formed by wall portion 50, there are several cantilevered fingers 51, or spring arms, that are designed to grip and hold an installed retaining member. When a retaining member is inserted into the indentations 44 and twisted, the twisting action causes a protruding edge of an extension 22 (shown in FIG. 1) to push into and bend the finger 51 to allow the extension to be turned past the location of the finger. Once the protruding edge of an extension passes the location of the finger, the finger springs back to nearly its original shape, so that surface 53 rests against the perimeter of the extension 22. This allows the cleat to be removed, but only by exerting sufficient force to bend the finger 51 away from the surface of the extension 22, an arrangement requiring much greater torque than that required during installation of the retaining member. In one embodiment, the fingers are elongated in shape, with surface 53 forming a curved tip to the finger. FIG. 6 also shows bumps 55 which serve as a means for preventing a retaining member from being turned too far. In a preferred embodiment, the cleat should not be turned more than about 60°. Coincident with the fingers 51 locking into place, the protruding edge of an extension is blocked from further movement by the bumps 55, and the entire retaining system is prevented from falling out of the receptacle by ledges 46. FIG. 6 also shows one method of attaching the receptacle to the underside of footwear by the use of mounting holes 57.

Spacing within the receptacle may be designed such that during installation of a cleat, the cavity 40 in which the extension is turned gradually narrows to compress and securely hold the cleat in place. Preferably the spacing is consistent or more gradual than the angled surface, so that the angled surfaces 24 (shown in FIG. 1) of the extension 22 being pressed against the ledges 46 cause the fit to be tight. In addition, having three extensions parallel to the cleat skirt makes for a more secure base for a cleat.

FIG. 7 is a vertical section of a portion of the embodiment of the receptacle of FIG. 6. This view shows the ledge 46 formed by the bottom layer 45 of the receptacle and the wall portion 50 that defines the cavity within the receptacle. This view also shows the slight rise 48 which forms a lip at the receptacle opening so that the edge of an installed cleat's skirt may overlay the lip. The lip helps hold the cleat in place and makes it more resistant to lateral forces while the cleat is in use.

FIG. 8, which is the FIG. 6 receptacle where the top layer has not been removed, is a view from the top of the receptacle 30 in accordance with a preferred embodiment of the invention. This view shows the top side 67 of the mounting holes for attaching the receptacle.

FIGS. 9A-9D, 10 and 11 show a preferred embodiment of a cleat having the same basic characteristics and structural concerns of the FIGS. 1, 2, and 3 embodiments discussed hereinabove. Evident in FIG. 9A are the bottom side 17 b and top side 16 b of the plastic skirt 15 b, the ground-engaging head portion 10 b of the cleat, a base 13 b to which the plastic skirt and ground-engaging portion are attached and a retaining member 20 b, which in this case is a base 13 b with three rounded extensions 22 b, the extensions having an angled surface 24 b and being positioned around a central axis 28 b. FIGS. 9B-9D are respectively the perspective top, front, and left view of the FIG. 9A cleat.

Evident in FIG. 10 are the corresponding topside 16 b of the cleat skirt 15 b and the retaining member 20 b, with indentations 26 b. The extensions 22 b of the retaining member 20 b are used in conjunction with components inside the receptacle 84 of FIG. 12A, for locking in place a properly inserted retaining member 20 b. Locking in place occurs after inserting the retaining member 20 b into a mated receptacle opening 40 b shown in FIG. 12A, and torquing the retaining member. As with the FIG. 1 embodiment, upon inserting the retaining member 20 b into a receptacle 84, the angled surface 24 b (shown in FIG. 9A) of the extensions 22 b forces a gradual compression of the retaining member 20 b as it is inserted into the receptacle cavity 40 b, resulting in a tight connection giving stability while also serving to keep moisture and debris out of the attachment system.

Also evident in the FIG. 10 embodiment is a modification to the FIG. 2 embodiment, where the extensions 22 of FIG. 2 are modified to include an indentation 70 that further enhances the invention's resistivity to unlocking and its unintentional removal through normal use. Increased resistivity is effected by an interlocking of a cantilevered finger 74 (shown in FIG. 16) with the indentation 70. The cantilevered finger 74 corresponds to the cantilevered finger 51 of the FIG. 6 embodiment, in which the cantilevered finger 51 has been thickened to afford a greater resistivity to unintentional unlocking. Further, upon complete insertion of the retaining member 20 b into an appropriate receptacle 84 (shown in FIG. 12A), the end portion 90 of the cantilevered finger 74 rests within the indentation 70. Consequently, removal of the cleat requires greater torque than that required to install the cleat.

FIG. 11 is another view showing the structure and proportion of the retaining member 20 b as attached to traction gear 21 b, indicating the location of indentation 70, as well as showing that the placement of the retaining member 20 b and base 13 b is concentrically disposed around the center axis 28 b.

FIG. 12A is a section view of a preferred embodiment of a receptacle for receiving the cleat of FIGS. 9A-9D, 10 and 11, where the top layer of the receptacle 84 has been removed to show the inner-cavity structure for receiving the retaining member 20 b (shown in FIG. 9A). FIG. 12B shows a perspective view of the FIG. 12A receptacle. As with the FIG. 6 embodiment, included within the cavity, formed by wall portion 78, are several cantilevered fingers 74 designed to grip and hold an installed retaining member 20 b. When a retaining member is inserted and twisted, the twisting action causes a protruding edge of an extension 22 b to push into and bend the finger 74 to allow the extension to be turned past the location of the finger. Once the protruding edge of an extension passes the location of the finger 74, the finger springs back to nearly its original shape, so that end portion 90 contacts the perimeter of the extension 22 b. As described hereinabove, when the end portion 90 contacts extension 22 b, there is an interlocking of cantilevered finger 74 with the indentation 70 (shown in FIG. 10). This allows the cleat to be removed, but only by exerting sufficient force to disengage and bend finger 74 away from indentation 70 and the surface of the extension 22 b, an arrangement requiring much greater torque than that required during installation of the retaining member. As with the FIG. 6 embodiment, the fingers are preferably elongated in shape, end portion 90 forms a curved tip to the finger, and bumps 55 b serve as a means for preventing a retaining member from being turned too far during insertion.

Also evident in the FIG. 12A receptacle is another preferred embodiment for attaching the receptacle 84 to the underside of footwear by the use of a mounting slot 80. In this embodiment, the perimeter 100 of the receptacle 84 comprises three flanges disposed around the receptacle opening 40 b. In preferred embodiments, within each flange 82 of the perimeter are two slots 80 for mounting the receptacle 84 to footwear. Mounting of the receptacle is by methods known in the prior art, and may include forming sole material around the slots, or inserting a pin or other object through the slot to effectively nail the receptacle to an inner-sole of a shoe, and then forming the outer-sole material around the receptacle so affixed. The slots 80 are separated by a pre-determined distance and are preferably curved to conform to the curvature of the flange 82 in which the slot 80 is set. Also shown are three openings 88 to allow for attaching a receptacle cover 96 (shown in FIG. 14) to the receptacle 84.

FIG. 13 is a vertical section of a portion of the embodiment of the receptacle of FIG. 12A. The FIG. 13 embodiment has a ridge 76 has been added in the bottom layer 86 of the wall portion 78 of the receptacle. In this preferred embodiment, the ridge 76 is located upon the downward side of the receptacle and helps assure mold seal-off. Sealing off the mold helps prevent sole material from the outsole molding process from accidentally spilling in over the bottom-end of the receptacle during production. (The receptacle and outsole are preferably molded ground-side up.) In addition, by adding ridge 76 to the basic design of FIG. 6, the structure of the FIG. 6 receptacle is strengthened, making it less susceptible to torques, distortions, or other forces. This results in better retention of the receptacle within the sole of athletic footwear.

FIG. 14 shows a receptacle cover 96 having three holes 92 corresponding to the three openings 88 shown in FIG. 12. In preferred embodiments, the receptacle cover is designed to attach to and seal the top end of the receptacle 84 of FIG. 12A, so that during molding of a shoe sole around the receptacle, the sole material does not seep under the top edge of the receptacle and fill its cavity. In addition, at the center of the cover 96 is a dome 94. This dome hangs downward from the top of the receptacle, into the receptacle cavity for receiving a retaining member 20 b (shown in FIG. 9A).

FIG. 15 shows a side view of the FIG. 14 cover, indicating the extent of the dome 94 with respect to the rest of the cover's 96 proportions. The dome forms a cavity 98 between a sole of a shoe and the top of the receptacle 84 (shown in FIG. 12A). In preferred embodiments, during manufacture of a shoe sole, in addition to sole material being molded around the receptacles, sole material is also allowed to fill in the cavity 98. Consequently, as a retaining member 20 b (shown in FIG. 9A) is inserted into a proper receptacle, the insertion forces a compression of the dome which in turn compresses the sole material filling the dome. The dome 94 serves two purposes. First, when the retaining member 20 b of traction gear is fully installed within a receptacle 84 (shown in FIG. 12A), the compression of the dome results in a downward pressure upon the extensions 22 b from the dome trying to re-expand into its original shape. Second, when one tries to remove the traction gear from the receptacle 84, the re-expansion of the sole material helps push the retaining member away from the sole, thus aiding in the removal of attached gear.

In preferred embodiments, the extensions for the attachment system are molded using conventional molding processes. Preferably, the molding process uses mold components having expandable cavities, these cavities allowing for undercuts to be molded without the use of side actions or slides. The receptacle may be molded using conventional molding processes, where the receptacles are preferably produced on a horizontal or vertical press and, with the aid of precision mold design and building, are formed in a manner well-known in the art.

In preferred embodiments of the invention, during manufacture, the receptacle portion with the top cover attached is placed in an outsole mold, and the ground surface part of a shoe is then molded. The molding process is preferably one of injection or compression molding. The particular location of each receptacle within the mold depends on the intended use of the shoe and the design of the shoe's shape. During manufacture of the outsole of one embodiment of the invention, mold support-braces may be used to help ensure no deformation of the receptacles during the molding of the sole. Preferably, the support-braces are negatives of the receptacle's shape such that when a brace is inserted into a receptacle, the receptacle 84 and pin holes 88 (shown in FIG. 12A) are temporarily sealed off to prevent sole material from filling in the receptacle cavity 40 b and pin holes 88. These pins may also be used to help orient and position the receptacle so that sole material flows up to and not beyond the ridge 76 (shown in FIG. 13) that is visible on the ground side of the receptacle. Once the outsole is molded, a second material may be molded or cemented to the outsole, and also cemented to the upper portion of the shoe. In this embodiment, the outsole and second material combination form a completed sole having the embedded receptacles.

In some embodiments, the shoe sole may be formed of light-weight materials such as EVA or foam. In such embodiments, the sole material may be insufficiently strong to hold a receptacle firmly in place. Consequently, in preferred embodiments, a support plate may be added to the sole structure, wherein the receptacles are attached to the plate at the desired locations, and the sole is formed around the attached receptacles. Such plates may also be used for heel support for footwear having light-weight heels; similarly, for heel-plates, support-pins may also be used to help prevent heel receptacle deformation.

FIG. 16 is a partial view of a FIG. 9A cleat inserted into a FIG. 12A receptacle. Shown is a magnified view of the end portion 90 of a cantilevered finger 74 at rest in indentation 70 of retaining member 20 b. As described hereinabove, after installation of a cleat into a receptacle, the torque required to dislodge the cantilevered finger 74 from the indentation 70 is much greater than that required during installation.

FIG. 17, a bottom view of the FIG. 9A cleat, shows that in this embodiment of the invention, a three-pronged wrench is inserted into the three wrench holes 110 used to remove the cleat. Use of a three-wrench-hole design gives greater stability during insertion and removal of a cleat, and allows greater torque to be applied, without slipping out of the holes, during such insertion and removal.

FIG. 18 is a top view of an alternate embodiment where a modified FIG. 14 cover is attached to the FIG. 12A receptacle through a flexible attachment region 120. In this embodiment, the receptacle 84 and cover 96 may be integrally formed of a single portion of production material, and simultaneously formed from a single mold. Before insertion of this embodiment of the receptacle into a shoe sole, the cover is flipped closed to cover the top of the receptacle. The FIG. 14 cover is modified to include two cover flanges 122 which, when the cover is closed, rest in-between two of the receptacle flanges 82. The cover flanges 122 also have slots 124, which in addition to the receptacle slots 80 described hereinabove, are used for mounting the FIG. 18 combined receptacle and cover to the underside of footwear.

FIG. 19 is a bottom view of the FIG. 18 embodiment, showing the ridge 76 (see FIG. 13 hereinabove) which helps prevent sole material from the outsole molding process from accidentally spilling in over the bottom-end of the receptacle opening 40 b with attached FIG. 14 cover having the features as disclosed hereinabove for FIG. 12A and FIG. 14.

FIG. 20 is a top section view of FIG. 18, showing the relationship between the extent of the dome 94 and the receptacle 84. Also shown is the region defined by portions 126, 128 for receiving the cover flange 122 when the cover is closed over the receptacle 84.

FIG. 21 shows a side view of an alternative embodiment of a cleat having some of the same basic characteristics of the FIGS. 1, 2, and 3 embodiments discussed hereinabove. Evident in FIG. 21 are a bottom 201 of a plastic skirt 203, and a top 205 with receptacles 207 for a cleat wrench. The cleat also has a ground-engaging spike 209 and a base 211 to which the skirt 203 and the spike 209 are attached. FIG. 22 is a side view of another cleat with a cleat connector similar to FIG. 21 showing an alternative ground-engaging “soft” golf spike 225. FIG. 23 is a top view of the cleat connector of the cleats in FIGS. 21 and 22 showing retaining member 213, which in this case is the base 211 with three thermoplastic extensions 215 projecting radially outward in a direction perpendicular to a vertical axis 210 of the base 211 in FIG. 21. Each extension 215 has a front side 217 approximately parallel to a radial midline 218 of the extension 215 and which extends from a radial end 220 of the extension 215 back towards the vertical axis 210 of the base 211. Each extension 215 also has a back side 219, roughly parallel to and substantially shorter than the front side 217; the back side 219 is also closer to the midline 218 of the extension 215 than the front side 217. The back side 219 extends back from the radial end of the extension 220, partway to the base 210 until it joins another surface 221 which is substantially perpendicular to the radial midline of the extension 218, so as to form an L-shaped indentation 222. In a preferred embodiment, the extensions 215 all lie in the same plane, and each extension 215 is equidistant from the adjacent extension.

FIG. 24 is a perspective top view of a preferred embodiment of a receptacle 251 for receiving the cleats of FIGS. 21, 22, and 23 with the top cover removed to show the inner-cavity structure for receiving the retaining member, 213 in FIG. 23. Within a cavity 253, formed by wall portion 255, are several protuberances 257 designed to grip and hold an installed retaining member 213. When a retaining member 213 is inserted and twisted, the twisting action rotates the front side 217 of an extension 215 past a protuberance 257 so that the radial end 220 of the extension 215 compresses the protuberance 257, allowing the extension 215 to turn past the protuberance 257. The extension 215 can continue to rotate until the front side 217 of the extension 215 engages a stopping wall portion 259 of the cavity 253. The receptacle 250 is designed so when the front side 217 of an extension 215 engages a stopping wall portion 259 of the cavity 253, the protuberance 257 springs back to nearly its original shape and snugly engages the L-shaped indentation 222 on the back side 219 of the extension 215. Each extension 215 of an installed cleat, therefore, is firmly held in place between a stopping wall 259 and a protuberance 257 so that the retaining member 213 is securely attached to the receptacle 250.

Removal of the cleat requires rotation in the opposite direction from installation. In a preferred embodiment, the protuberances 257 and the radial ends 220 of the extensions 215 are shaped so that rotation of the cleat in the removing direction requires much greater torque than that required during installation. For example, the radial ends 220 of the extension 215 may be tapered on the front side, 223 in FIG. 23, so that the radial end more easily rides over and compresses the protuberance during installation. Without a taper on the back side 224 of the radial end of the extension 215, substantially greater force is required for the radial end 220 to ride over and compress the protuberance 257 when rotation is in the removing direction. Alternatively, the protuberances 257, rather than the extensions 215, may be tapered to allow easier rotation in the installation direction and require greater force for rotation in the removing direction.

FIG. 25 is a top view of a cleat connector 260 of the type shown in FIG. 23, with the addition of semi-circular dust covers 261 between each extension 215. Of course, the cleat connector 260 may be placed on top of a wide variety of surface engaging structures including both surface penetrating structures and non-surface penetrating structures. FIG. 26 is a perspective top view of the cleat connector 260 of FIG. 25, and FIG. 27 is a perspective top view of a preferred embodiment of a receptacle 262 for receiving the cleat connector 260 of FIG. 25. To install the cleat, the connector extensions 215 are inserted into the receptacle's semicircular openings 263. The cleat is rotated into place to engage the structure of the connector 260 with the internal structure of the receptacle 262 as described above with respect to FIGS. 23 and 24. This also rotates the dust covers 261 towards the receptacle openings 263. As the connector 260 locks into place in the receptacle 262, the dust covers 261 settle snugly into the receptacle openings 263 to seal the openings 263 so as to prevent the entry of debris from the ground into the receptacle 262.

As shown in FIG. 28, the dust covers 261 may have an incline so that as the connector 260 rotates into place in the receptacle 262, the leading edge 264 of the dust cover 261 is lower, or closer to the base of the connector 260 than is the trailing edge 265 of the dust cover 261. As a result, as the cleat is rotated, the dust cover 261 initially rotates easily over the opening 263 of the receptacle 262. Before the structure of the connector 260 locks into engagement with the internal structure of the receptacle 262, the higher trailing edge 265 of the dust cover 261 becomes compressed by the edge of the opening 263 of the receptacle 262 increasing the amount of force required to rotate the cleat. Just as the structure of the connector 260 locks into engagement with the internal structure of the receptacle 262, the trailing edge 265 of the dust cover 261 clears the edge of the opening 263 of the receptacle 262. This releases the compression of the trailing edge 265 of the dust cover 261 which springs down into the opening 263 of the receptacle 262. Thus, the vertical face of the trailing edge 265 of the dust cover 261 fits against the edge of the opening 263 of the receptacle 262 so as to form a secondary lock in addition to the primary lock of the structure of the connector 260 in engagement with the internal structure of the receptacle 262. In addition to sealing against the entry of debris into the receptacle 262, the secondary lock formed by the dust covers 261 in engagement with the opening 263 of the receptacle 262, provides additional resistance against the undesired unlocking rotation of the installed cleat in high torque environments such as with baseball cleats.

FIG. 27 also shows a receptacle 262 with a receptacle cover 266 having a cover spring 267 which extends into a receptacle cavity defined by the receptacle openings 263. The receptacle spring 267 performs two functions similar to that of the dome 94 in FIGS. 14 and 15. First, when a cleat connector 260 is installed so as to engage the structure of the receptacle 262, the receptacle spring 267 is compressed and thereby exerts a downward pressure on the cleat connector 260 which increases the contacting force between the connector 260 and the receptacle 262. Second, when the cleat is rotated for removal from the receptacle 262 (e.g., for replacement), the receptacle spring supplies an ejecting force on the cleat connector 260 which aids in disengaging the cleat connector 260 from the receptacle 262.

These functions do not necessarily require the use of a dome 94 as in FIGS. 14 and 15, or a spring 267 as in FIG. 27. FIG. 29 shows a receptacle cover 268 having a center cone 269. The cone 269 performs the same functions as the previously discussed dome 94 and spring 267. In addition, the size and strength of the cone 269 may be relatively substantial when the cleat connector 260 contains a similarly shaped mating depression 270, shown in FIGS. 25 and 26.

It should be realized that while the various preferred embodiments of cleat receptacles differ in the complexity of their specific structures, this does not significantly restrict the materials which may be used to fabricate such receptacles. All or part of a receptacle may be fabricated from metal. Alternatively, all or part of receptacle may be fabricated from a synthetic material such as plastic or nylon. Metal offers great strength, but with relatively great weight. Synthetic materials may be relatively lighter, while somewhat less strong than metal. Either metal or synthetic materials may, however, be employed satisfactorily.

In the preceding description and following claims, the term “cleat” is consistently used, however, no distinction is intended to be created between cleats and spikes, nor should any be inferred. In addition, while preferred embodiments have been described in which a cleat may be removably attached to a shoe using the described connectors and receptacles, the use of such connectors and receptacles is not limited to attaching cleats to shoes, but may be generally employed as a removably attachable connector system in other applications which require the attachment of one mechanical structure to another. Similarly, it is of course apparent that the present invention is not limited to the detailed description set forth above. Various changes and modifications of this invention as described will be apparent to those skilled in the art without departing from the spirit and scope of this invention as defined in the following claims. 

What is claimed is:
 1. A cleat attachment system for footwear, comprising: a cleat receptacle in a sole of the footwear, the receptacle having an opening and a cleat engaging structure including at least three equally spaced radial receptacle projections; and a rotationally attachable cleat having a vertical axis with first and second ends, including: at the first end, a ground engaging member; and at the second end, an attachment structure including at least three equally spaced radial cleat projections, each cleat projection: (i) being asymmetric with respect to an axis projecting radially outward from the center of the attachment structure through the radial center of the projection, and (ii) the radial center of the projection having a convex curved radial end; wherein the receptacle projections interact with the cleat projections so that less force is required to engage the cleat with the receptacle than to disengage the cleat from the receptacle.
 2. A system according to claim 1, wherein the cleat is made substantially of thermoplastic.
 3. A system according to claim 1, wherein the receptacle is made substantially of thermoplastic.
 4. A system according to claim 1, further comprising: a skirt located between the first end and the second end, the skirt extending radially outward beyond the radial ends of the extensions.
 5. A system according to claim 1, wherein the cleat projections and the receptacle projections interact in a plane substantially transverse to the vertical axis of the cleat.
 6. A system according to claim 1, wherein the cleat rotates substantially less than one full turn when engaging with the receptacle.
 7. A system according to claim 1, wherein the cleat rotates substantially less than one full turn when disengaging from the receptacle.
 8. A system according to claim 1, wherein, as the cleat is installed into the receptacle, each cleat projection has a rotationally leading edge and a rotationally trailing edge, each receptacle projection engaging the rotationally trailing edge of an installed cleat so as to resist loosening rotation of the cleat.
 9. A rotationally attachable cleat for footwear having a vertical axis with first and second ends, the cleat comprising: a ground engaging member at the first end; and an attachment structure at the second end including at least three equally spaced radial cleat projections, each cleat projection: (i) being asymmetric with respect to an axis projecting radially outward from the center of the attachment structure through the radial center of the projection, and (ii) the radial center of the projection having a convex curved radial end; wherein, the cleat projections are capable of interacting with a corresponding cleat receptacle so that less force is required to engage the cleat with the receptacle than to disengage the cleat from the receptacle.
 10. A cleat according to claim 9, wherein the cleat is made substantially of thermoplastic.
 11. A cleat according to claim 9, further comprising: a skirt located between the first end and the second end, the skirt extending radially outward beyond the radial ends of the extensions.
 12. A cleat according to claim 9, wherein the cleat projections are capable of interacting with the receptacle in a plane substantially transverse to the vertical axis of the cleat.
 13. A cleat according to claim 9, wherein the cleat rotates substantially less than one full turn when engaging with the receptacle.
 14. A cleat according to claim 9, wherein the cleat rotates substantially less than one full turn when disengaging from the receptacle.
 15. A cleat according to claim 9, wherein, when the cleat is installed into the receptacle, each cleat projection has a rotationally trailing edge capable of engaging the receptacle so as to resist loosening rotation of the cleat. 